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Notes1.4


sea-floor spreading - is the process of expanding the ocean floor
sonar - a device that bounces sound waves under-water object
mid-ocean ridge - the longest chain of mountain covered with water
deep-ocean trenches - deep ocean trenches forms when the oceanic crust is bent downward
subduction - the process by which the ocean floor sinks beneath a deep ocean trench



outline


Introduction

  • East Pacific Rise
    • you can find giant, red-tipped tube worms
    • mid ocean ridge
    • hot water vents
    • evidence for the sea-floor spreading

Mapping the Mid-Ocean Ridge

  • East Pacific Rise is one part of the mid-ocean ridge
  • mid-1900's, scientists mapped the mid-ocean ridge using sonar

Evidence for the Sea-floor spreading

  • evidence from molten material
  • evidence from magnetic strips
  • evidence from drilling sample

Subduction at deep ocean trenches

  • convection currents push new crust to deep-ocean trenches
  • sinking crust is like washcloth

Subduction and Earth's Oceans

  • Subduction in the Pacific Ocean
  • Subduction in the Atlantic Ocean